Cranial deformities for an otherwise normal child can result from aberrant constraint of the fetal head during late uterine life. Plagiocephaly can also contribute to facial asymmetry.
In some subjects with plagiocephaly, the head will correct its shape over time, but with others the condition may persist as a cosmetic disability. Given the latter possibility, it is desirable to attempt correction of the deformation when the subject is less than a year old and preferably during the first six months of life when the brain and cranium are growing at a rapid rate and the sutures in the cranium have not rigidified.
Researchers in this field have previously discovered that confining the cranium within a specially shaped helmet can result in remodeling the cranium as it expands against the helmet with growth. One such effort has been reported by S. K. Claren, D. W. Smith, and J. W. Hanson in the January 1979 issue of The Journal of Pediatrics (Volume 94, No. 1) at Pages 43-46 in an article entitled "Helmet Treatment for Plagiocephaly and Congenital Muscular Torticollis". That article is incorporated herein by reference.
S. K. Claren of the aforementioned research team disclosed what he deemed to be an improved helmet treatment in his U.S. Pat. No. 4,776,324, granted Oct. 11, 1988, for "Therapeutic and Protective Infant Helmets". He proposed the use of a graded series of sized helmets to replace the previously used individualized helmets.
There are a number of short-comings or disadvantages associated with helmet treatment of plagiocephaly. The first of these is the result of the passive nature of the helmet treatment which relies entirely on cranial growth to provide the pressure necessary for remodeling to occur. At any given time, the pressure delivered to the cranium may be sub-optimal, optimal, or excessive, depending on the extent of the subject's cranial growth.
The helmet is quite confining and the virtual absence of air circulation therein can result in excessive sweating with little evaporative cooling. The helmet is uncomfortable.
Furthermore, in order for the helmet to be easily removed and replaced, the cranial entry opening therein must have a circumference at least as great as the largest occipitofrontal circumference of the subject's misshapen cranium. As a consequence, the helmet is relatively ineffective to correct cranial deformation distal to and beneath the apex of the cranial deformity. This same requirement for the configuration of the helmet also dictates that a chin strap must be employed to keep the helmet in place. The chin strap can apply deforming forces to the subject's jawbone and interfere with eating and chewing.
There continues to be a need for an improved orthosis for cranial remodeling.